Over the 8 years of my acquaintance with computers valuable data has been lost at an average of twice per annum. I have tried all kinds of solution to help my situation only to fail miserably by forgetting to back up some important bits and pieces of information before upgrading my distro.

Backup solutions can mostly be factored into two approaches of archiving and cloning. If space is limited, you can archive your important data using utilities such as tar. This in fact was the approach I had been using until now. The downside appeared to be lesser accessibility of the files inside the backup. Say, I needed a small text-file from a 200 GB archive. It’d take me around 20 minutes to “get” to its location in the archive.

Which is why, I decided to shift to a newer approach. My laptop has a 320 GB hard disk and I own another 320 GB Western Digital Passport for extra data. To utilize the similitude, I bought another 500 GB Passport, transferred the “extra” data to it and then cloned the entire laptop hard disk to its 320 GB external cousin.

$ ddif=/dev/sda of=/dev/sdb

$ dd if=/dev/sda of=/dev/sdb

That is all. dd‘s performance was questionable, as it took around 15 hours to clone the entire 320 GB. Nevertheless, this time around I was satisfied with the final backup. Not only was it a bit-by-bit replica of my original data but also an accessible repository which I could access easily by plugging in the USB.

Yesterday I needed to copy the MBR of a drive over another. Googling a little I found the following command in various tutorials:

-bash-$ ddif=/dev/sda of=/dev/sdb bs=512count=1

-bash-$ dd if=/dev/sda of=/dev/sdb bs=512 count=1

Where /dev/sda and /dev/sda were the original and target hard disks respectively. The command did complete its work in a snap but it also made me learn a thing about MBR structures the hard way: Only 446 bytes of the MBR contain boot code, the next 64 contain the partition table!

The implications of the lesson being, if partition tables of both hard disks differ — which unfortunately was the case with me — the partition table of the target hard-disk will be overwritten. The correct way would therefore be:

-bash-$ ddif=/dev/sda of=/dev/sdb bs=446count=1

-bash-$ dd if=/dev/sda of=/dev/sdb bs=446 count=1

In case you did mess up the table, I recommend TestDisk for recovering your partitions.

“For the wise man looks into space and he knows there is no limited dimensions.” — Lao Tzu

I’ve always suspected that pornography has a history with mankind but I never guessed that the founder of Taoism had already been downloading enough to foresee virtually limitless data capacity needs. History repeated itself as I logged in yesterday just to notice that the free space on my hard disk was about 400 MB. Panic time, and the only efficient solution I could work out was to buy a Western Digital 320 GB portable hard drive.

Now, these days, buying any digital storage medium which has its capacity advertised in GBs is subject to the 7.2% deficit rule (I just conjured this name so I can’t be held responsible if it doesn’t occupy an entry in Wikipedia yet). The rule is simple: For every digital storage that you buy, you won’t ever see 7.2% of the GBs quoted on the product. Which means, if you buy a 250 GB hard drive, you’ll only be able to use 232 GB. For my 320 GB buy, I lose 320 x 7.2% = 23.04 and end up with 296.96 GB. Unless you’re prepared to tackle the difference between powers of 2 and 10, don’t even bother questioning the origins of this rule.

So, the passport drive came bundled with some software for synchronization and encryption. Did I bother? No. I reformatted it straight away as an Ext3 partition. After that, TrueCrypt and rsync were more than enough to cater for all my needs without any hassle. For the curious, here’s the command that I used to synchronize my home directory:

This would exclude all hidden directories, and synchonize the /media/Inspirated/Home to mirror the exact state of /home/krkhan. The fun part, for those unfamiliar with rsync, is that if I synchronize, let’s say, fortnightly; only the data newer since last backup is copied.

I hope it would be least a couple of years before I get to quote Lao Tzu again.